Water availability on the Third Pole: A review

The Third Pole is the headwater region for Asian major rivers providing water for millions of people inside and around. Driven by rainfall and snowfall with large spatial and temporal variation in their amount, water availability reviewed here is buffered by snow, glaciers, groundwater and springs. Most glaciers have been losing mass contributing to annual excess discharge. Significant depletions of groundwater and drying up of many springs are observed in some areas of the region. Summary of runoff components across the region shows rainfall is the major contributor, followed by snow and glacier melt, though their relative contribution varies among basins. Modelling studies project a changing seasonality of river runoff, increased extremes and a high variability among the river basins.